Coney Island’s fabled beachfront area would become home to America’s largest urban amusement park, about 4,500 new apartments and a bunch of major retail establishments under a grand plan unveiled today by Mayor Bloomberg.

The goal of the rezoning plan is to turn the rundown summer amusement area into a year-round attraction – but without giving up the freakishness for which Coney is so well known.

City renderings show the new amusement park incorporating the landmark Cyclone roller coaster and Wonder Wheel with new indoor and outdoor attractions – including a new, looping roller coaster winding around the park and a new, iconic ride rivaling the size and shape of the 262-foot-high Parachute Jump.

Property at the base of the Wonder Wheel would be set aside for an ice skating/roller skating rink.

“When you combine that with the aquarium and with KeySpan Park, we will have 50 contiguous acres of public park with the best in recreation that Brooklyn or New York has to offer,” Bloomberg said.

The mayor’s plans for a new 21st Century Coney Island seem to signal a death knell for developer Thor Equities’ controversial $1.5 billion proposal to build a Vegas-glitz entertainment complex in the heart of the amusement district. The administration isn’t providing zoning needed for that project to break ground.

But Bloomberg’s long-anticipated plan includes rezoning 47 acres of prime Coney Island real estate running along the boardwalk from W. 24th Street east to the New York Aquarium on W. 8th Street.

The proposed zones set aside 15 acres for the amusement park running from Stillwell Avenue east to the Aquarium – much of which is part of the existing Astroland Park site and other land owned by Thor CEO Joe Sitt.

The city would need to acquire Sitt’s land and other privately owned parcels before choosing a partner to develop the urban amusement park.

World-famous Tivoli Gardens in Copenhagen has expressed interest in expanding to Coney Island, as have other amusement operators.

Land directly above the new park near Surf Avenue – some of which is also owned by Sitt – is expected to someday house hotels totaling 500 to 600 units, indoor and outdoor performance venues, retail space, restaurants and a movie theater, officials said.

About 20 percent – or 900 – of the 4,500 units of new housing would be set aside as affordable for low- and middle-income families.

The entire rezoning plan must go through the city’s land use review process, which includes public hearings and requires approval of the City Council and other governing bodies. City officials said they have no immediate plans to acquire any private land through eminent domain.

The city hopes to break ground in 2009 and that the overall project would take 10 to 20 years to complete.